Safety-tread for steps.



'Nea 875,440.

PATENTED DEG, s1. 1907, J s. LAMSON. SAFETY TRBAD FOR STEPS.

APPLICATION FILED FEB 11. 1905.

parmis lstrain `frnnr mica.

WILLAM S. LAMSON, OF LOWELL, MASSACHUSETTS, ASSGNOR TOA AMERICAN MASON SAFETY TREAD COMPANY, OF SACO, MAINE, A CORPORATION OF MAINE. y

SAFETY-TRE AD FOR STEPS.

Specification of Letters Patent.

Patented Dec. 31, 1907.

Application filed February 11,1905. Serial No. 245.318-

T o all whom. it may concern:

Be it known that l, WILLIAM S. LAMsoN, a citizen of the United States, residing at Lowell, in the countyof Middlesex and Commonwealth of Massachusetts, have invented a certain new and usefullmprovement lin Safety-Trcads for Steps, of which the following is a specification.

This invention, relates to safety-treads, particularly for use on car-steps and stairways where the traffic is heavy and the vwear is great and where there is unusual danger of slipping.

.The object of this invention is to provide a tread surface consisting of non-slipping rough or irregular artificial stone,-such as granular or ground corundum, bicarborundum or similar grits or substance mixed with and united by a suitable binding substance,- said stone' being secured in a base, frame or bed-plate of metal or material softer than said stone, in order that the adjacent clamping portions of the bed-plate may wear faster than the non-slipping stone port-ions and leave the latter exposed to contact.

vhile l do not confine myself to the exact4 form or material of the`base` frame or bedplate of the tread, 'l wish to state that in practice l have found it convenient to use a, grooved bed-plate substantially like what is shown and described in United States patent, No. 481,702, to Mason, Mason and Codner and to mix up the stone composition in the form o'f a thick paste or mortar and to fill the grooves, channels orpockets of the bed l plate therewith, allowing the same to harden in the grooves. The filling may be applied by a masons trowel-in the usual manner. v

I have found that a mixture ofcalcined magnesite, groundcarborundum (silicide of carbon) made into a cement or mortar with magnesium chlorid and placed in. the grooves of the plate, becomes very hard and non-yielding after a few hours and serves a very satisfactory purpose. Thisl composition is very convenient for use and q-uickly becomes much harder than the bed-plate, the latter being preferably of mild steel, and is not deteriorated by rain or moisture or by changes of temperature.

Sand or cmery may be substituted for the whole or any part of the carborundum.

In the accompanying drawing, Figure l,

is a plan of a tread constructead according to my invention and Fig. 2, a vertical section of the same on'the line 2 2 in Fig. 1.

The drawing illustrates the best method ofv construction known to me at present.

A is a base-plate or bed-plate of castor wrought metal, metallic alloy, or other suitable substance with raised ribs a and'undercut or dovetail grooves b between said ribs substantially as shown and described in said y patent. These plates may be produced by rolling, as therein described, or by other conf venient means or methods, said plates not being of my invention T he grooves I) are fllled with a suitable plastic mixture c capable when it sets of becoming harder than the bed-plate and of forming an artificial stone preferably of a porous nature.

The base-plate .may be of any material adapte-d to retain the filling orstone, pro-y vided said material be suitable for that purpose and be sufficiently softer than said filling, so that as the. tread surface is worn down, the non-slipping composition or stone .will always come to the wearing surface.

I claim as my invention 1. A non-slipping treadfor ste shaving its treadsurface com osed of arti cialstone and having a base or ame of materialsofter than said stone.

2. A non-slipping vtread for ste s having its tread-surface composed of arti cial stone containing carborundum, and havinga suitable base or frame softer than carbo-rundum to contain said stone.

'3. A non-slipping tread for ste shaving its tread-surface composed of car orundum or other hard artificial porous stone, and with a suitable body of metal softer than the carborundum, said metal forming the founda tion or basis of the step.

4. A tread for steps consisting of a metal base, provided with suitable channels or pock-v ets filed with grits, held therein by an artificial stone cement and forming a non-yielding grit tread-surface.

-5. A tread for steps consisting of a metal base provided with suitable dovetail channels or pockets filled with grits, held therein by a suitable cement and forming a non-yielding grit tread-surface.

6. A tread step consisting of a metal base, provided with suitable 'channels or pockets filled with hard-crystal stone grits, held within the said channels or pockets by an artificial'stone cement, in .such a manner as to filled with a plastic Composition containing forrn a non-yielding irregular surface, subl. 9. A non-slipping tread Consisting of a stantially as specified. l grooved base plate, the grooves whereof are 7. A tread step consisting of a metal base illed with a self-hardening plastic oo1nposiprovided with suitable dovetail Channels or tion containing an abrasive. pockets 'filled with hard Crystal stone grits, 10. A grooved plate, the groove or grooves held within the said channels or pockets by a l suitable cement in such a manner as to forni l Capable of .hardening on exposure.

In testimony' whereof, -I have aflixed my signature, in presence of two Witnesses.

VlLLlAM S. LAMSON.

a non-yielding irregular grit tread surface, substantially as described.

8. A non-slipping tread consisting of a grooved base plate, the grooves whereof are Witnesses:

ALBERT M. MOORE,

an abrasive, allowed to harden therein. GRACE CROWLEY.

whereofare iilled with a plastic gritty cement 

